
<!DOCTYPE HTML>
<html lang="zh-hans" >
    <head>
        <title>mountLazyComponent · React源码解析</title>
        <meta charset="UTF-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
        <meta name="description" content="">
        <meta name="generator" content="GitBook 3.2.0">
        
        
        
    
    <link rel="stylesheet" href="../../../gitbook/style.css">

    
            
                
                <link rel="stylesheet" href="../../../gitbook/gitbook-plugin-highlight/website.css">
                
            
                
                <link rel="stylesheet" href="../../../gitbook/gitbook-plugin-search/search.css">
                
            
                
                <link rel="stylesheet" href="../../../gitbook/gitbook-plugin-fontsettings/website.css">
                
            
                
                <link rel="stylesheet" href="../../../gitbook/gitbook-plugin-theme-api/theme-api.css">
                
            
        

    

    
        
        <link rel="stylesheet" href="../../../styles/website.css">
        
    
        
    
        
    
        
    
        
    
        
    

         
    
    
    <meta name="HandheldFriendly" content="true"/>
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black">
    <link rel="apple-touch-icon-precomposed" sizes="152x152" href="../../../gitbook/images/apple-touch-icon-precomposed-152.png">
    <link rel="shortcut icon" href="../../../gitbook/images/favicon.ico" type="image/x-icon">

    
    <link rel="next" href="update-functional-component.html" />
    
    
    <link rel="prev" href="mount-indeterminate-component.html" />
    

<script
  async
  src="https://www.googletagmanager.com/gtag/js?id=UA-49483742-5"
></script>
<script>
  window.dataLayer = window.dataLayer || []
  function gtag() {
    dataLayer.push(arguments)
  }
  gtag('js', new Date())

  gtag('config', 'UA-49483742-5')
</script>

    </head>
    <body>
        
<div class="book">
    <div class="book-summary">
        
            
<div id="book-search-input" role="search">
    <input type="text" placeholder="输入并搜索" />
</div>

            
                <nav role="navigation">
                


<ul class="summary">
    
    

    

    
        
        
    
        <li class="chapter " data-level="1.1" data-path="../../../">
            
                <a href="../../../">
            
                    
                    首页
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2" >
            
                <span>
            
                    
                    基础
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.2.1" data-path="../../api/react.html">
            
                <a href="../../api/react.html">
            
                    
                    React API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.2" data-path="../../api/react-element.html">
            
                <a href="../../api/react-element.html">
            
                    
                    ReactElement
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.3" data-path="../../api/react-children.html">
            
                <a href="../../api/react-children.html">
            
                    
                    React Children
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.2.4" data-path="../../api/react-structure.html">
            
                <a href="../../api/react-structure.html">
            
                    
                    React 中的数据结构
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.3" >
            
                <span>
            
                    
                    创建更新
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.3.1" data-path="../../update/react-dom-render.html">
            
                <a href="../../update/react-dom-render.html">
            
                    
                    ReactDOM.render
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.2" data-path="../../update/set-state.html">
            
                <a href="../../update/set-state.html">
            
                    
                    setState & forceUpdate
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.3" data-path="../../update/expiration-time.html">
            
                <a href="../../update/expiration-time.html">
            
                    
                    expirationTime 计算
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.4" >
            
                <span>
            
                    
                    任务调度
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.4.1" data-path="../scheduler-global.html">
            
                <a href="../scheduler-global.html">
            
                    
                    全局变量
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.2" data-path="../schedule-work.html">
            
                <a href="../schedule-work.html">
            
                    
                    scheduleWork
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.3" data-path="../scheduler-pkg.html">
            
                <a href="../scheduler-pkg.html">
            
                    
                    react-scheduler
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.4" data-path="../perform-work.html">
            
                <a href="../perform-work.html">
            
                    
                    performWork
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.5" data-path="../perform-unit-of-work.html">
            
                <a href="../perform-unit-of-work.html">
            
                    
                    performUnitOfWork
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.6" data-path="../render-root.html">
            
                <a href="../render-root.html">
            
                    
                    renderRoot
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.4.6.1" data-path="../render-root/throw-exception.html">
            
                <a href="../render-root/throw-exception.html">
            
                    
                    throwException
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.4.7" data-path="../begin-work.html">
            
                <a href="../begin-work.html">
            
                    
                    beginWork
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.4.7.1" data-path="mount-indeterminate-component.html">
            
                <a href="mount-indeterminate-component.html">
            
                    
                    mountIndeterminateComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter active" data-level="1.4.7.2" data-path="mount-lazy-component.html">
            
                <a href="mount-lazy-component.html">
            
                    
                    mountLazyComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.3" data-path="update-functional-component.html">
            
                <a href="update-functional-component.html">
            
                    
                    updateFunctionalComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.4" data-path="update-class-component.html">
            
                <a href="update-class-component.html">
            
                    
                    updateClassComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.5" data-path="update-host-root.html">
            
                <a href="update-host-root.html">
            
                    
                    updateHostRoot
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.6" data-path="update-host-component.html">
            
                <a href="update-host-component.html">
            
                    
                    updateHostComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.7" data-path="update-host-text.html">
            
                <a href="update-host-text.html">
            
                    
                    updateHostText
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.8" data-path="../../feature/Suspense-component.md">
            
                <span>
            
                    
                    updateSuspenseComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.9" data-path="update-portal-component.html">
            
                <a href="update-portal-component.html">
            
                    
                    updatePortalComponent
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.10" data-path="update-forward-ref.html">
            
                <a href="update-forward-ref.html">
            
                    
                    updateForwardRef
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.11" data-path="update-fragment.html">
            
                <a href="update-fragment.html">
            
                    
                    updateFragment
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.12" data-path="update-mode.html">
            
                <a href="update-mode.html">
            
                    
                    updateMode
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.13" data-path="update-profiler.html">
            
                <a href="update-profiler.html">
            
                    
                    updateProfiler
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.14" data-path="update-context-provider.html">
            
                <a href="update-context-provider.html">
            
                    
                    updateContextProvider
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.7.15" data-path="update-context-consumer.html">
            
                <a href="update-context-consumer.html">
            
                    
                    updateContextConsumer
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.4.8" data-path="../reconcile-children.html">
            
                <a href="../reconcile-children.html">
            
                    
                    reconcileChildren
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.4.8.1" data-path="../reconcile-children/single.html">
            
                <a href="../reconcile-children/single.html">
            
                    
                    调和单个节点
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.8.2" data-path="../reconcile-children/array.html">
            
                <a href="../reconcile-children/array.html">
            
                    
                    调和列表
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.5" >
            
                <span>
            
                    
                    commit 阶段
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.5.1" data-path="../../commit-phase/commit-root.html">
            
                <a href="../../commit-phase/commit-root.html">
            
                    
                    commitRoot
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.2" data-path="../../commit-phase/invokeGuardedCallback.html">
            
                <a href="../../commit-phase/invokeGuardedCallback.html">
            
                    
                    invokeGuardedCallback
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.3" data-path="../../commit-phase/commitBeforeMutationLifecycles.html">
            
                <a href="../../commit-phase/commitBeforeMutationLifecycles.html">
            
                    
                    commitBeforeMutationLifecycles
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.4" data-path="../../commit-phase/commit-all-host-effects.html">
            
                <a href="../../commit-phase/commit-all-host-effects.html">
            
                    
                    commitAllHostEffects
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.5.4.1" data-path="../../commit-phase/host-effects/CommitPlacement.html">
            
                <a href="../../commit-phase/host-effects/CommitPlacement.html">
            
                    
                    commitPlacement
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.4.2" data-path="../../commit-phase/host-effects/CommitWork.html">
            
                <a href="../../commit-phase/host-effects/CommitWork.html">
            
                    
                    commitWork
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.4.3" data-path="../../commit-phase/host-effects/CommitDeletion.html">
            
                <a href="../../commit-phase/host-effects/CommitDeletion.html">
            
                    
                    commitDeletion
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.5.5" data-path="../../commit-phase/commit-all-lifecycles.html">
            
                <a href="../../commit-phase/commit-all-lifecycles.html">
            
                    
                    commitAllLifecycle
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.6" >
            
                <span>
            
                    
                    功能
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.6.1" data-path="../../features/context.html">
            
                <a href="../../features/context.html">
            
                    
                    context
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.2" data-path="../../features/hydrate.html">
            
                <a href="../../features/hydrate.html">
            
                    
                    hydrate
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.3" data-path="../../features/ref.html">
            
                <a href="../../features/ref.html">
            
                    
                    ref
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.4" data-path="../../features/event-injection.html">
            
                <a href="../../features/event-injection.html">
            
                    
                    事件系统初始化
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.5" data-path="../../features/event-bind.html">
            
                <a href="../../features/event-bind.html">
            
                    
                    事件绑定
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.6" data-path="../../features/event-dispatch.html">
            
                <a href="../../features/event-dispatch.html">
            
                    
                    事件触发
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.7" data-path="../../features/event-create-event-object.html">
            
                <a href="../../features/event-create-event-object.html">
            
                    
                    事件对象生成
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.8" data-path="../../features/Suspense-component.html">
            
                <a href="../../features/Suspense-component.html">
            
                    
                    Suspense
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.9" data-path="../../features/suspense.html">
            
                <a href="../../features/suspense.html">
            
                    
                    挂起任务的含义
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.10" data-path="../../features/suspense-lazy.html">
            
                <a href="../../features/suspense-lazy.html">
            
                    
                    lazy 组件
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.7" >
            
                <span>
            
                    
                    Hooks
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.7.1" data-path="../../hooks/hooks-start.html">
            
                <a href="../../hooks/hooks-start.html">
            
                    
                    开始
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.2" data-path="../../hooks/hooks-use-state.html">
            
                <a href="../../hooks/hooks-use-state.html">
            
                    
                    useState
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.3" data-path="../../hooks/hooks-use-effect.html">
            
                <a href="../../hooks/hooks-use-effect.html">
            
                    
                    useEffect
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.4" data-path="../../hooks/hooks-others.html">
            
                <a href="../../hooks/hooks-others.html">
            
                    
                    其他API
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.7.5" data-path="../../hooks/hooks-common.html">
            
                <a href="../../hooks/hooks-common.html">
            
                    
                    通用API
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    

    

    <li class="divider"></li>

    <li>
        <form
            action="https://buttondown.email/api/emails/embed-subscribe/Jokcy"
            method="post"
            target="popupwindow"
            onsubmit="window.open('https://buttondown.email/Jokcy', 'popupwindow')"
            class="buttondown-form"
            >
            <input type="email" name="email" id="bd-email" placeholder="(your@email.com)">
            <input type="hidden" value="1" name="embed"/>
            <button type="submit">订阅我</button>
        </form>
    </li>
</ul>

                </nav>
            
        
    </div>

    <div class="book-body">
        
            <div class="body-inner">
                 
                    

<div class="book-header" role="navigation">
    

    <!-- Title -->
    <h1>
        <i class="fa fa-circle-o-notch fa-spin"></i>
        <a href="../../.." >mountLazyComponent</a>
    </h1>
</div>




                    <div class="page-wrapper" tabindex="-1" role="main">
                        <div class="page-inner">
                            
<div id="book-search-results">
    <div class="search-noresults">
    
                                <section class="normal markdown-section">
                                
                                <div class="api-method"><div class="api-method-definition"><h1 id="mountlazycompont">mountLazyCompont</h1><p>&#x4E3A;&#x4EC0;&#x4E48;&#x8981;&#x53EB;<code>mount</code>&#x800C;&#x4E0D;&#x662F;<code>update</code>&#x5462;&#xFF1F;&#x56E0;&#x4E3A;<code>lazy</code>&#x7EC4;&#x4EF6;&#x53EA;&#x6709;&#x5728;&#x52A0;&#x8F7D;&#x7684;&#x7EC4;&#x4EF6;&#x8FD8;&#x6CA1;&#x5B8C;&#x6210;&#x4E4B;&#x524D;&#x624D;&#x4F1A;&#x88AB;&#x6267;&#x884C;&#xFF0C;&#x7B49;&#x5230;&#x52A0;&#x8F7D;&#x5B8C;&#x6210;&#x4E86;&#xFF0C;&#x90A3;&#x4E48;&#x5C31;&#x53D8;&#x6210;&#x52A0;&#x8F7D;&#x4E4B;&#x540E;&#x7684;&#x7EC4;&#x4EF6;&#x4E86;&#xFF0C;&#x6C38;&#x8FDC;&#x4E0D;&#x4F1A;&#x6267;&#x884C;&#x5230;&#x81EA;&#x5DF1;&#x7684;&#x66F4;&#x65B0;&#x3002;</p><p>&#x8FD9;&#x4E5F;&#x662F;&#x4E00;&#x5F00;&#x59CB;&#x5224;&#x65AD;<code>current</code>&#x662F;&#x5426;&#x5B58;&#x5728;&#x7684;&#x539F;&#x56E0;&#xFF0C;&#x5982;&#x679C;&#x5B58;&#x5728;&#x5219;&#x4E0D;&#x7B26;&#x5408;&#x7EC4;&#x4EF6;&#x7684;&#x671F;&#x671B;&#xFF0C;&#x9700;&#x8981;&#x91CD;&#x65B0;&#x6309;&#x7167;<code>current</code>&#x4E0D;&#x5B58;&#x5728;&#x7684;&#x65B9;&#x5F0F;&#x8FDB;&#x884C;&#x66F4;&#x65B0;&#x3002;</p><p>&#x6838;&#x5FC3;&#x65B9;&#x6CD5;&#x662F;<code>readLazyComponentType</code></p><pre><code class="lang-js"><span class="hljs-keyword">export</span> <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">readLazyComponentType</span>&lt;<span class="hljs-title">T</span>&gt;(<span class="hljs-params">lazyComponent: LazyComponent&lt;T&gt;</span>): <span class="hljs-title">T</span> </span>{
  <span class="hljs-keyword">const</span> status = lazyComponent._status;
  <span class="hljs-keyword">const</span> result = lazyComponent._result;
  <span class="hljs-keyword">switch</span> (status) {
    <span class="hljs-keyword">case</span> Resolved: {
      <span class="hljs-keyword">const</span> Component: T = result;
      <span class="hljs-keyword">return</span> Component;
    }
    <span class="hljs-keyword">case</span> Rejected: {
      <span class="hljs-keyword">const</span> error: mixed = result;
      <span class="hljs-keyword">throw</span> error;
    }
    <span class="hljs-keyword">case</span> Pending: {
      <span class="hljs-keyword">const</span> thenable: Thenable&lt;T, mixed&gt; = result;
      <span class="hljs-keyword">throw</span> thenable;
    }
    <span class="hljs-keyword">default</span>: {
      lazyComponent._status = Pending;
      <span class="hljs-keyword">const</span> ctor = lazyComponent._ctor;
      <span class="hljs-keyword">const</span> thenable = ctor();
      thenable.then(
        moduleObject =&gt; {
          <span class="hljs-keyword">if</span> (lazyComponent._status === Pending) {
            <span class="hljs-keyword">const</span> defaultExport = moduleObject.default;
            <span class="hljs-keyword">if</span> (__DEV__) {
              <span class="hljs-keyword">if</span> (defaultExport === <span class="hljs-literal">undefined</span>) {
                warning(
                  <span class="hljs-literal">false</span>,
                  <span class="hljs-string">&apos;lazy: Expected the result of a dynamic import() call. &apos;</span> +
                    <span class="hljs-string">&apos;Instead received: %s\n\nYour code should look like: \n  &apos;</span> +
                    <span class="hljs-string">&quot;const MyComponent = lazy(() =&gt; import(&apos;./MyComponent&apos;))&quot;</span>,
                  moduleObject,
                );
              }
            }
            lazyComponent._status = Resolved;
            lazyComponent._result = defaultExport;
          }
        },
        error =&gt; {
          <span class="hljs-keyword">if</span> (lazyComponent._status === Pending) {
            lazyComponent._status = Rejected;
            lazyComponent._result = error;
          }
        },
      );
      lazyComponent._result = thenable;
      <span class="hljs-keyword">throw</span> thenable;
    }
  }
}</code></pre>
<p>&#x9ED8;&#x8BA4;<code>status</code>&#x662F;<code>-1</code>&#xFF0C;&#x6267;&#x884C;&#x4F20;&#x5165;&#x7684;&#x65B9;&#x6CD5;&#x5F97;&#x5230;<code>thenable</code>&#x65B9;&#x6CD5;&#xFF0C;&#x6839;&#x636E;<code>thenable</code>&#x7684;&#x7ED3;&#x679C;&#x66F4;&#x65B0;&#x7EC4;&#x4EF6;&#x7684;&#x72B6;&#x6001;&#xFF0C;&#x5E76;&#x4E14;&#x628A;<code>resolve</code>&#x7684;&#x7EC4;&#x4EF6;&#x8FDB;&#x884C;&#x8FD4;&#x56DE;</p><p>&#x8FD4;&#x56DE;&#x7EC4;&#x4EF6;&#x4E4B;&#x540E;&#x6267;&#x884C;&#x4E86;&#x4EE5;&#x4E0B;&#x51E0;&#x53E5;&#x4EE3;&#x7801;&#xFF0C;&#x975E;&#x5E38;&#x91CD;&#x8981;&#xFF1A;</p><pre><code class="lang-js">workInProgress.type = Component;
<span class="hljs-keyword">const</span> resolvedTag = (workInProgress.tag = resolveLazyComponentTag(Component));</code></pre>
<p>&#x4ED6;&#x628A;<code>lazy</code>&#x7EC4;&#x4EF6;&#x7684;<code>Fiber</code>&#x5BF9;&#x8C61;&#x7684;<code>tag</code>&#x548C;<code>type</code>&#x90FD;&#x6539;&#x53D8;&#x4E86;&#xFF0C;&#x4E0B;&#x6B21;&#x6267;&#x884C;&#x5230;&#x8FD9;&#x4E2A;<code>Fiber</code>&#x7684;&#x66F4;&#x65B0;&#xFF0C;&#x5219;&#x4F1A;&#x76F4;&#x63A5;&#x66F4;&#x65B0;&#x8FD4;&#x56DE;&#x7684;<code>type</code></p></div><div class="api-method-code"><div class="api-method-sample" data-lang="js" data-name="JavaScript"><pre><code class="lang-js"><span class="hljs-comment">// &#x5173;&#x952E;&#x4EE3;&#x7801;</span>
<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">mountLazyComponent</span>(<span class="hljs-params">
  _current,
  workInProgress,
  elementType,
  updateExpirationTime,
  renderExpirationTime,
</span>) </span>{
  <span class="hljs-keyword">if</span> (_current !== <span class="hljs-literal">null</span>) {
    <span class="hljs-comment">// An lazy component only mounts if it suspended inside a non-</span>
    <span class="hljs-comment">// concurrent tree, in an inconsistent state. We want to tree it like</span>
    <span class="hljs-comment">// a new mount, even though an empty version of it already committed.</span>
    <span class="hljs-comment">// Disconnect the alternate pointers.</span>
    _current.alternate = <span class="hljs-literal">null</span>;
    workInProgress.alternate = <span class="hljs-literal">null</span>;
    <span class="hljs-comment">// Since this is conceptually a new fiber, schedule a Placement effect</span>
    workInProgress.effectTag |= Placement;
  }

  <span class="hljs-keyword">const</span> props = workInProgress.pendingProps;
  <span class="hljs-comment">// We can&apos;t start a User Timing measurement with correct label yet.</span>
  <span class="hljs-comment">// Cancel and resume right after we know the tag.</span>
  cancelWorkTimer(workInProgress);
  <span class="hljs-keyword">let</span> Component = readLazyComponentType(elementType);
  <span class="hljs-comment">// Store the unwrapped component in the type.</span>
  workInProgress.type = Component;
  <span class="hljs-keyword">const</span> resolvedTag = (workInProgress.tag = resolveLazyComponentTag(Component));
  startWorkTimer(workInProgress);
  <span class="hljs-keyword">const</span> resolvedProps = resolveDefaultProps(Component, props);
  <span class="hljs-keyword">let</span> child;
  <span class="hljs-keyword">switch</span> (resolvedTag) {
    <span class="hljs-keyword">case</span> FunctionComponent: {
      child = updateFunctionComponent(
        <span class="hljs-literal">null</span>,
        workInProgress,
        Component,
        resolvedProps,
        renderExpirationTime,
      );
      <span class="hljs-keyword">break</span>;
    }
    <span class="hljs-keyword">case</span> ClassComponent: {
      child = updateClassComponent(
        <span class="hljs-literal">null</span>,
        workInProgress,
        Component,
        resolvedProps,
        renderExpirationTime,
      );
      <span class="hljs-keyword">break</span>;
    }
    <span class="hljs-keyword">case</span> ForwardRef: {
      child = updateForwardRef(
        <span class="hljs-literal">null</span>,
        workInProgress,
        Component,
        resolvedProps,
        renderExpirationTime,
      );
      <span class="hljs-keyword">break</span>;
    }
    <span class="hljs-keyword">case</span> MemoComponent: {
      child = updateMemoComponent(
        <span class="hljs-literal">null</span>,
        workInProgress,
        Component,
        resolveDefaultProps(Component.type, resolvedProps), <span class="hljs-comment">// The inner type can have defaults too</span>
        updateExpirationTime,
        renderExpirationTime,
      );
      <span class="hljs-keyword">break</span>;
    }
    <span class="hljs-keyword">default</span>: {
    }
  }
  <span class="hljs-keyword">return</span> child;
}</code></pre>
</div></div></div>




                                
                                </section>
                            
    </div>
    <div class="search-results">
        <div class="has-results">
            
            <h1 class="search-results-title"><span class='search-results-count'></span> results matching "<span class='search-query'></span>"</h1>
            <ul class="search-results-list"></ul>
            
        </div>
        <div class="no-results">
            
            <h1 class="search-results-title">No results matching "<span class='search-query'></span>"</h1>
            
        </div>
    </div>
</div>

                        </div>
                    </div>
                
<div id="disqus_thread"></div>
<script>
  /**
   *  RECOMMENDED CONFIGURATION VARIABLES: EDIT AND UNCOMMENT THE SECTION BELOW TO INSERT DYNAMIC VALUES FROM YOUR PLATFORM OR CMS.
   *  LEARN WHY DEFINING THESE VARIABLES IS IMPORTANT: https://disqus.com/admin/universalcode/#configuration-variables*/
  /*
var disqus_config = function () {
this.page.url = PAGE_URL;  // Replace PAGE_URL with your page's canonical URL variable
this.page.identifier = PAGE_IDENTIFIER; // Replace PAGE_IDENTIFIER with your page's unique identifier variable
};
*/
  ;(function() {
    // DON'T EDIT BELOW THIS LINE
    var d = document,
      s = d.createElement('script')
    s.src = 'https://react-source-code.disqus.com/embed.js'
    s.setAttribute('data-timestamp', +new Date())
    ;(d.head || d.body).appendChild(s)
  })()
</script>
<noscript
  >Please enable JavaScript to view the
  <a href="https://disqus.com/?ref_noscript"
    >comments powered by Disqus.</a
  ></noscript
>

            </div>

            

        
    </div>

    <script>
        var gitbook = gitbook || [];
        gitbook.push(function() {
            gitbook.page.hasChanged({"page":{"title":"mountLazyComponent","level":"1.4.7.2","depth":3,"next":{"title":"updateFunctionalComponent","level":"1.4.7.3","depth":3,"path":"book/flow/begin-work/update-functional-component.md","ref":"book/flow/begin-work/update-functional-component.md","articles":[]},"previous":{"title":"mountIndeterminateComponent","level":"1.4.7.1","depth":3,"path":"book/flow/begin-work/mount-indeterminate-component.md","ref":"book/flow/begin-work/mount-indeterminate-component.md","articles":[]},"dir":"ltr"},"config":{"plugins":["theme-api"],"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"sharing":{"facebook":false,"twitter":false,"google":false,"weibo":true,"instapaper":false,"vk":false,"all":["weibo","google","twitter","weibo","instapaper"]},"highlight":{},"search":{},"lunr":{"maxIndexSize":1000000,"ignoreSpecialCharacters":false},"fontsettings":{"theme":"white","family":"sans","size":2},"theme-api":{"languages":[],"split":true,"theme":"light"},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false}},"theme":"default","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"README.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"title":"React源码解析","language":"zh-hans","gitbook":"*"},"file":{"path":"book/flow/begin-work/mount-lazy-component.md","mtime":"2019-01-28T08:33:58.850Z","type":"markdown"},"gitbook":{"version":"3.2.0","time":"2019-07-08T12:28:32.264Z"},"basePath":"../../..","book":{"language":""}});
        });
    </script>
</div>

        
    <script src="../../../gitbook/gitbook.js"></script>
    <script src="../../../gitbook/theme.js"></script>
    
        
        <script src="../../../gitbook/gitbook-plugin-search/search-engine.js"></script>
        
    
        
        <script src="../../../gitbook/gitbook-plugin-search/search.js"></script>
        
    
        
        <script src="../../../gitbook/gitbook-plugin-lunr/lunr.min.js"></script>
        
    
        
        <script src="../../../gitbook/gitbook-plugin-lunr/search-lunr.js"></script>
        
    
        
        <script src="../../../gitbook/gitbook-plugin-sharing/buttons.js"></script>
        
    
        
        <script src="../../../gitbook/gitbook-plugin-fontsettings/fontsettings.js"></script>
        
    
        
        <script src="../../../gitbook/gitbook-plugin-theme-api/theme-api.js"></script>
        
    

    </body>
</html>

